[Radiance-general] sky visibility

[Lars O. Grobe]

Hi Ji!

The functions S(n) and T(n) are available in pcomb. To make an image "solid_angles.hdr" with pixel values (r=g=b) being equal to the solid angle of the pixel in sr, you would do the following:

cat image.hdr |  pcomb -e 'omega=S(1); ro=omega; go=omega; bo=omega' -o - > solid_angles.hdr

So S(n) gives, for each pixel of the n'th input image, its solid angle. To take a look, use falsecolor -m 1 -s .000008 -ip solidangle.hdr | ximage - good way to think about projections...

Cheers, Lars.


> Hi, Lars, thanks a lot for your advices!
> 
> May I ask the references on the S and T function as you suggested to look up? (I didn't find any relevant infor via Radiance forum search...)
> 
> May I also ask what the "n" in the "S(n)" denotes? 
> 
> Thanks again!
> 
> - Cheers, Ji